Different size elements array copying with IRBuilder API?

Heya, I’m really new here, so please excuse me if this is not appropriate room for this question, and please feel free to lead me to the correct one.

I need to copy int(32bit) elements array to the long(64 bit) elements array:
Something like this:
int a[10];
long b[10];
for(int i=0; i < 10; ++i)
b[i] = a[i];

But it should be done via LLVM 10 instructions(IRBuilder API) and without a loop.
Do you have any ideas?